© 2006 Carlos Chegado, All Rights Reserved.
The oyster shells have been dropped by fishermen and buried in the middle of the river mud for many years - until the new catamaran boats from Soflusa arrived. These new boats that carry passengers from Barreiro to Lisbon on the other side of the river have a water jet propulsion that digs into the riverbed and makes such waves that carry the oyster shells to the beach. Once there, the shells started to accumulate in a manner that looks very much like a levee.
Although this looks like someone has been carefully putting oyster shells to make a levee, this is not the case, I live nearby and have seen these shells grow in number in the last couple of years, making a distinct borderline in this part of the Tejo river.